Dolphin

Yesterday started out poorly. I only slept for 4 hours. After waking up at 4am, I headed over to my computer. There was a notification from Ebay about some US Electricar stuff that went up for auction. As it turns out, it was the same hardware that one of the guys in the USE group had mentioned was for sale. We thought it would be a private sale. But here it was on Ebay. I immediately posted that fact that it was on Ebay to the group. The boards were all suppose to be 65kw. But only 2 were 65kw, the other 6 were 50kw boards. So I looked at the name of the seller, and it looked vaguely familiar. I searched my email archives and found that I had corresponded with the guy in the past. So I wrote him a plea to not sell them on Ebay since some random buyer could end up with these important parts. He agreed to pull them from Ebay and sell them to me. Sometime later this week they should arrive. Also included were 2 charger boards and a dc-dc board. There was also 4th board that I have never seen before.

What I have done in the past with two other batches of boards I have received,
is to go through these boards carefully with my test fixture, and see if they
work or what they need to make them work. One 50kw board looks to have some
serious damage to the Mach220. I have replaced a couple Mach220’s already. But
that serious kind of damage may also have toasted some board traces. Worst case
the board becomes a parts donor. I hope the DSP chip is ok as it could be used
in another 50kw board. Almost every chip from the 50kw boards are missing. Since
the DSP chip cannot be copied, then the boards will always have to borrow a DSP
from another board.

The 65kw boards will go onto my test fixture to see if they can be lit up or
not. At least they have all of their chips. I’ll see if the 65kw chips are any
different than the 50kw chips. At least one of the 65kw boards has a red arrow
on it indicating that it needs something.

5 out of 6 of the 50kw boards are 2nd generation. They have a socket on the
Mach220 plus some other additions. I think the factory finally figured out that
when the Mach220 gets damaged, that unsoldering it from the board is dangerous.
At least with the sockets the Mach220’s can be swapped in and out for testing. I
have the code for the Mach 220’s so duplicating them is easy.

There is also a pair of charger boards and a dc-dc included. There is a 4th misc
board that I have never seen before. No idea what it does.

I know of 2 other sources that need boards. So if any of the 50kw boards are any
good, 2 of them will get shipped out asap. Usually when the chips are missing
the boards have issues.

All of the boards that run will have to be test driven to see if they exhibit
any of the classic dropout issues. As I was discussing the dropout issue last
night with a fellow member, he pointed out that every board we have could end up
with severe drop out issues just simply from driving them long enough. That is
exactly what has happened with a couple of the boards that I have. To me this
issue is 50% resolved. The last 50% will be tough.

I finally got around to putting fuses in the P12V_Bat and Key_On_In lines on the #1 truck. I tried to use 1/4 amps fuses, but the current drop was so much that the Dolphin would not boot. They measured 5 ohms on each fuse. I measured several and they were all the same. So I went with 1.0 amp fuses that measured about .3 ohms each. Very clean. I’ve done the same thing to the #2 truck. It was much easier to spend 3 minutes removing the junction boxes from the trucks and doing the work on a bench.

I also put a spring inside the 3/4 inch heater hose that was kinking. It now has a nice curve to it. The spring is just plated steel. We’ll see how long it lasts. At least this way the new high performance heater will always get adequate coolant flow to protect the heater element from overheating.

Isn’t debug fun? It sure separates the boys from the men, or me from my sanity Wink

I’ll be on vacation starting Monday. That excuse one for not having my BMS installed. #2 is that the second truck has taken all of my time to get corrections made to it’s various electrical systems. It’s basically done. Just needs a new pack. So the #1 truck is the tough vehicle to get a shielded cable from the pack to the interior of the truck. Once the cable is mounted through the wall of the pack, then adding the BMS is easy. Now I have Thundersky’s that I have been testing as well as 3 new 50ah Hi Power cells to test.

To look for noise it’s helpful to determine if it’s conducted or radiated noise. Steps that I use.

Conducted Emissions

1) I like to use clip on ferrite beads for initial debug. Easier and faster than adding components. The kind you see attached to a wall wart power supply or your pc monitor cable. 25-30mm long. 15-20mm in diameter. When picking them up from surplus locations, get a few different versions as you don’t know which RF material they are made from. Clip them onto both ends of the master bus cable. One at the master board and one at the first slave. Check for changes. Does the system work better? Verify with a scope, always.

2) Now repeat step one with the Slave bus, with all of the master bus ferrites removed. The slave bus could easily carry EMI/RFI and cause issues.

3) Repeat step one with ferrites on Master and Slave bus.

4) The shotgun approach is to just do both Master and Slave bus at the same time. But you won’t know the sources of noise as well.

If 1-4 improve function then it’s the noise is mostly conducted emissions. Although radiated emissions from the vehicle could turn into conducted emissions due to the huge amount of wiring we have to use.

5) Always twist pairs of cables to 4 turns per 25.4mm(1 inch) between slaves. Cordless drill works great for twisting wires together.

6) Use shielded cables with twisted pairs for Master to first slave cables.

Radiated Emissions

Here is a fantastic article on how to make a home made probe for sniffing EMI/RFI with your scope from a piece of coax a tiny ferrite bead, and some sandpaper. When I showed the crew at work this article, everyone had me making these probes for them.

Below are scope shots using my probe on a project that has so much EMI that it smoked the processor and other drivers badly enough that my head with a full face helmet, hit the ground hard and made me unconscious. Had a concussion for a year. So EMI and I have become great friends!

There are EMI and RFI (aka E field) probes. An E field probe is just the ground of your scope probe tied to the probe tip. It shorts it in a dc sense. But for RFI, it’s a path to joy and harmony. If you make your probe ground lead a bit longer and coil it, the probe becomes much more sensitive to weak signals.

Both EMI and RFI probing examples of my concussion making machine (a home made self balancing scooter) are shown here.

These scope shots showed me clearly at the time where the emissions were coming from. Each output from the processor got a 1k resistor to isolate it from the drivers. A 1k resistor was put on the output of the driver chips. These two steps did not reduce EMI, but did reduce it from getting into the sensitive parts. The next step was to reduce the EMI itself. I had used 250mm long ribbon cables for connecting the master board to two slaves (control board to 2 H-bridge boards). Normally the ribbon cables are about 50mm long. Reinstalling the 50mm cables did the trick. The EMI probe showed me the way. As you can see from the scope shots I also found EMI from the power supply inductor as well that I could follow with my handy EMI probe along a ground trace. That’s right. EMI was following the ground!!

It sure looks like the schematic for the precharge board is done. I see something that does not make sense yet it matches the original board perfectly. It was a fair amount of work. But I’ve noticed that the #2 truck has a hard time booting up sometimes. I think the 24k miles on it has worn out the precharge relay. The #1 truck is on it’s second precharge relay. Commuting with the #1 truck will surely wear out it’s second precharge relay, quickly too.

At some point I need to get a board made and start testing it before the precharge relay goes out completely on the #2 truck. I may also make a 2nd board layout that is exactly the same as the original board. Right now the components are in the same place but the traces are routed differently. At least I did find all of the data sheets for the parts. The capacitors were the toughest to find by far. I do need to open a Dolphin and look at those two tapped holes on the Dolphin floor to see if they match up to the holes in the original precharge board. That would be nice if all Dolphins were tapped to mount a precharge board!!

The precharge relay in the USE vehicles is not durable enough to keep charging the capacitors from zero volts to 312vdc nominal, then taking them back down to zero volts. This precharge board is from a 65kw USE system. The goal is to duplicate the circuit and install it in both trucks as is it not available anywhere on the planet. This could seriously increase the precharge circuit reliability. I noticed years ago that there are a couple of tapped holes on the floor of the Dolphin. I wonder if holes 5 and 6 on this board match that hole pattern on the floor of the Dolphin?

Take a look at the charger board. It has a 13 pin connector on it with
a harness that leads to the connector at the back-center of the main
board. Notice the pattern of the wires in the charger connector.
(1)–(4)–(7)(8)-(10)(11)(12)(13). The dashes are empty. Start
counting from the position that is closest to the front of the truck.
Add 1 amp, 250vac fuses to positions 1, 4. Then add 1/4 amp (any
voltage)fuses to positions 7, 8. One and four is the AC voltage going
to the main board. Seven and eight is the pwm that goes from the main
board to the charger.

The last 1 amp fuse goes to terminal #19 in the junction box. If you
look at the schematic you can see which side to add the fuses to. Some
say the side with the tiny gauge wire. But when I do mine I will be
adding it to the side with the pair of large gauge wires. One wire of
the pair comes from the 12v aux battery, the other wire goes off to
the Magnecharger.

Dolphin processor programming board. If you have a 5B5AA processor and upload a full set of constants into the processor, it will prevent the vehicle from running due to a flaw in the 5B5AA code. At this point the code cannot be corrected. This is the board that will bring the nonfunctional processor back to life.